Tissue severing device having dual reciprocating looped blades and methods of use

ABSTRACT

Tissue severing devices having extension members that reciprocate distally and proximally and are coupled to dual reciprocating looped blades are disclosed herein. The severing devices described herein can be used during laparoscopic surgery to cut tissue of a predetermined diameter using the two looped blades.

FIELD OF THE INVENTION

The teachings herein relate to instruments useful in laparoscopicsurgery and methods of using said instruments. More specifically, theembodiments herein relate to tissue severing devices having dualreciprocating looped blades and methods of using these devices to cuttissue from a patient.

BACKGROUND

During laparoscopic surgical procedures and, more particularly, tissueremoval procedures, it is desirable to limit the size of the entryincision to minimize the trauma experienced by the patient. In the past,efforts to minimize entry incision size have generally been limited dueto the size of the tissue to be removed and the need for access to thetissue.

Morcellators are devices that morcellate, or cut tissue, into smallerpieces to allow for easier removal through small surgical access sites.Prior art morcellators that require a pushing or downward tractionoperation to cut the tissue present a danger of over extension intotissue that is not to be injured. By way of example, but not limitedthereto, during a laparoscopic subtotal hysterectomy, one way ofminimizing the danger of this over extension is to amputate the body ofthe uterus from the cervix prior to morcellation. The amputation of theuterus presents an added risk of injury to other nearby organs, such asthe rectum and bowel, as they lie behind the uterus and are difficult tosee during uterus amputation. Also, amputation is commonly performedusing electrocautery or harmonic scalpel which may cause lateral spreadof heat or other energy and can inadvertently cause a burn to the bowelor bladder that may not be realized until days after surgery. Further,amputation of the uterus requires the use of one surgical instrument toamputate the uterus and another surgical instrument to morcellate theuterus with their associated cost and complexity of use.

Some known laparoscopic morcellators utilize graspers that pull tissueinto a spinning tubular blade or the spinning blade is pushed into thetissue. These types of instruments have their limitations and dangersassociated with their use, non-exclusively including the exposed sharpblade possibly injuring surrounding tissue not intended to bemorcellated, discharge of the tissue in a spinning tool, and thedifficulty and dangers of placing downward traction into the targettissue. Currently, performing a morcellation through a laparoscope isdifficult as there are concerns about a spinning blade being pointingdownward toward the bowel. It is undesirable to use a spinning bladethat spits cut tissue throughout the abdominal cavity and that allowsfor cut tissue to drop onto other organs (bowel) in the abdominalcavity. Furthermore, these morcellators require both hands to be used bya surgeon, one to hold the spinning morcellator and the second for thegrasper that pulls the tissue through it. The need for two hands tomorcellate the tissue limits the surgeon to use his other hand to holdanother instrument or the laparoscope. Also, the need for a two handedapproach disallows the ability to design the instrument to be usedrobotically.

In order to make laparoscopic tissue removal safer without the need tofirst amputate the tissue, morcellators were designed to have a single,looped blade. According to one prior art embodiment, a blade wasdesigned to oscillate, such that the ends of the single looped bladewere configured to be rapidly and alternatively pulled on in a proximaldirection to impart a sawing motion to the cutting element's distal end.See, for example, U.S. Pat. No. 8,585,727 “Tissue Severing Devices andMethods”. However, while improving upon the safety of prior artmorcellators, the efficacy of using a single looped blade knife ismarkedly diminished by the short distance that the blade travels backand forth to make the cut. Another disadvantage with an oscillatingsingle looped blade is that the targeted tissue moves in the samedirection as the blade, making the attempted cut more difficult toperform.

Accordingly there is a need in the art to provide morcellator bladeassemblies that are safe for the patient, such that they cut in aproximal direction away from the targeted tissue and nearby organs andoscillate so that they don't splinter and hurl tissue into thesurrounding area as with a spinning blade. Additionally the assembliesshould also be more efficient at cutting the targeted tissue than asingle looped blade. The following disclosure describes cutting devicesthat solve this need in the art by utilizing reciprocating dual loopedblades.

Preferred embodiments are directed to tissue cutting devices comprising:an electric motor configured to be turned on and off; an external tubehaving an internal channel traversing lengthwise from proximal to distalends; first and second extension members having proximal and distalends, left and right lateral sides, and positioned superiorly andinferiorly to one another within the internal channel of the externaltube such that they traverse parallel with the length of the externaltube, wherein the proximal ends of the extension members are operablycoupled to the electric motor that drives straight reciprocating motionof the first and second extension members in alternate proximal anddistal directions with respect to each other, such that when the firstextension member is pushed distally the second extension member ispulled proximally, and vice versa; an outer looped blade having a firstend operably coupled to the first extension member; and a second endoperably coupled to the second extension member; and an inner loopedblade, positioned proximally and adjacent to the outer looped blade, andhaving a first end operably coupled to the first extension member and asecond end operably coupled to the second extension member; and whereinthe outer and inner looped blades are positioned distally to the distalend of the external tube, and configured to reciprocate in alternateclockwise and counter-clockwise directions and in opposite directionswith respect to each other as the first and second extension membersreciprocate proximally and distally.

Additional embodiments are directed to methods of cutting tissue from apatient comprising: providing the tissue cutting device; inserting thedistal end of the external tube into the patient; pulling the externaltube proximally exposing the looped blades; turning the electrical motoron to reciprocate the outer and inner looped blades in alternatingclockwise and counter-clockwise directions; cutting the tissue from thepatient with the reciprocating outer and inner looped blades; pushingthe external tube distally over the looped blades; and removing theexternal tube from the patient.

BRIEF DESCRIPTION OF THE DRAWINGS

It will be appreciated that the drawings are not necessarily to scale,with emphasis instead being placed on illustrating the various aspectsand features of embodiments of the invention, in which:

FIG. 1 is a perspective view of a cutting device in its neutral orclosed position.

FIG. 2 is a perspective view of a cutting device in a partially extendedposition.

FIG. 3 is a perspective view of a cutting device in its fully extendedposition.

FIG. 4A is a close-up top perspective view of U-shaped looped cuttingblades, with a crossbar, showing reciprocating motion in a firstdirection. FIG. 4B is a close-up top perspective view of U-shaped loopedcutting blades, with a crossbar, showing reciprocating motion in asecond direction.

FIG. 5A is a close-up perspective view of oval shaped looped cuttingblades, with extension members having flared distal ends, and showingmotion.

FIG. 5B is a close-up perspective view of extension members havingcutouts at their distal ends for use with oval shaped looped cuttingblades (not shown).

FIG. 6 shows cross sections of crossbars and the blades in astraightened configuration.

FIG. 7 shows cross sections of crossbars and the blades in astraightened configuration.

FIG. 8 shows a straightened view of an inner blade with extensions.

FIG. 9 shows straightened inner and outer blades with backstops alignedwith each other.

FIG. 10 shows straightened inner and outer blades with backstopsseparated from each other.

FIG. 11 is a close up view of a cutting device in a partially extendedposition.

FIG. 12 is a close up view of a cutting device in a fully extendedposition.

FIG. 13 is a close up view of ribbons coupled to oval shaped blades witha catching bag.

FIG. 14 is a close up view of cables within barrels coupled to U-shapedblades and crossbars, showing motion.

FIG. 15 is a top view of a beveled external tube with a swivelingcrossbar in an open position.

FIG. 16 is a top view of a beveled external tube with a swivelingcrossbar in a collapsing position.

FIG. 17 is a top view of an external tube with a bendable crossbar in anopen position.

FIG. 18 is a top view of an external tube with a bendable crossbar in acollapsing position.

FIG. 19 is a perspective view of a cutting device, lacking an internaltube, in its natural position.

FIG. 20 is a plan view of outer and inner looped blades in astraightened configuration

FIG. 21 is a plan view of superior and inferior extension members havingtabs.

FIG. 22 is a plan view of superior and inferior extension members havingpronged tabs.

FIG. 23 is an assembled perspective view of a cutting device havingouter and inner looped blades coupled to the tabs of the superior andinferior extension members.

FIG. 24 is an exploded perspective view of a cutting device having outerand inner looped blades and the distal sections of the superior andinferior extension members.

FIG. 25 is an exploded perspective view of a cutting device having outerand inner looped blades and the distal sections of the superior andinferior extension members having a semicylindrical shaped section.

FIG. 26 is a perspective view of a cutting device having a torsionspring being used to maintain the shape of the outer and inner loopedblades in its operable position.

FIG. 27 is an assembled perspective view of a cutting device havingouter and inner looped blades interchanged and coupled to the tabs ofthe superior and inferior extension members.

FIG. 28 is a perspective view of a cutting device having a torsionspring being used to maintain the shape of the interchanged outer andinner looped blades in its operable position.

FIG. 29 is a perspective view of a cutting device having an internaltube extending over the tabs of the extension members and the slits ofthe looped blades.

FIG. 30 is a perspective view of a cutting device having a telescopingexternal tube that is configured to slide proximal and distal.

FIG. 31 is a close-up exploded perspective view of the distal end of acutting device having extension members with cutouts at their distalends for use with cutting blades.

FIG. 32 is a close-up assembled perspective view of the distal end of acutting device having extension members with cutouts at their distalends for use with cutting blades.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Embodiments of the present invention are described below. It is,however, expressly noted that the present invention is not limited tothese embodiments, but rather the intention is that modifications thatare apparent to the person skilled in the art and equivalents thereofare also included.

Embodiments herein relate to a reciprocating severing device can be usedin laparoscopic surgery to cut tissue in cylindrical shaped (or otherdesired shapes such as oval, arched, and the like) pieces of apredetermined diameter. Once cut up, the pieces can be pulled through atrocar sleeve of a larger inside diameter.

The device can work independently through a separate trocar sleeveentering the body or can travel though a single, multiple channel sleeveadjacent to the laparoscope, and can be detachably coupled to thelaparoscope at its proximal end so that during operation they move inunison and function as a resectoscope. Alternatively, a narrowlaparoscope can be fitted to travel adjacent to the extension members,inside the instruments tube, on its long axis, so that it may alsofunction as a resectoscope.

FIGS. 1-3 show perspective views of a preferred cutting device 1. Thedevice 1 preferably includes two extension members, such as the rods 6and 7, positioned within an internal tube 2 that is positioned within anexternal tube 3. The extension members, e.g., rods 6 and 7, internaltube 2 and external tube 3 each have proximal and distal ends andpreferably run along the same axis. More specifically, it is preferredthat the extension members, e.g., rods 6 and 7 include a superiorextension member 6 and an inferior extension member 7 and that they arefixed parallel to one another, but configured to move in proximal anddistal directions.

Preferably, the extension members, e.g., rods 6 and 7 are flexible toallow bending as shown in FIGS. 3 and 12. However, it is preferable thatthe distal ends of the extension members 6 and 7 (distal to the bendableneck 7) are sufficiently rigid so the blades 4 and 5 do not bend whilecutting. Alternatively, the extension members can be substantially rigidthroughout and have necks that are bendable and that are aligned with abendable neck 11 of the internal tube 2. In yet another embodiment, notshown, both the inner tube and rods are flexible and symmetrically bendduring flexion. In all embodiments, the outer tube remains rigid.Suitable materials for the extension members include thin flexible yetstrong metals, including nitinol and stainless steel (e.g., springsteel), or fiberglass, for example. Additionally, embodiments can bedirected to extension members, that are substantially rigid and don'tbend.

The reciprocating extension members can have any suitable cross-section,including circular, semicircular, oval, square, hexagon, polygonal,rectangular, and the like. Likewise while the term rods are usedpredominantly herein, the broader term “extension member” is meant toencompass both rods 6 and 7 or ribbons 6′ and 7′ or cables 6″ and 7″,substantially flat extension members 100 and 102, 100′ and 102′ andsemicylindrical extension members 146 and 148, and these terms canreadily be substituted where suitable. As shown in FIG. 14, to keepcables 6″ and 7″ in an inferior to superior relationship, the insidetube can include an inferior rigid barrel 31 and a superior rigid barrel30, that sheath their respective cables 6″ and 7″.

As shown in FIG. 13, for ribbon embodiments, it is preferred that theparallel ribbons 6′ and 7′ are positioned with their flat sides facingtowards inferior and superior directions, with the superior ribbon 6′positioned above the inferior ribbon 7′. During motion, to keep theribbons from bowing away from each other, a segmental slot 28 can belocated on one ribbon 6′ and a pin 29 is fixed to the second ribbon 7′and configured to stay within the slot 28 such that the ribbons 6′ and7′ will not detach nor bow away from each other. The positioning of thesegmental slot 28 and pin 29 shown in FIG. 13 can be interchangedbetween the ribbons 6′ and 7′. The slot length 28 is at least of thelength of the maximum difference of proximal/distal travel of thereciprocating ribbons 6′ and 7′ (stroke length). Preferably ribbons 6′and 7′ are made of a flexible material with sufficient strength(rigidity) to maintain its shape when pushing and pulling the blades 4and 5. This can be a flexible thin material such as spring steel ornickel titanium, also known as nitinol, or fiberglass, for example.

The extension members, e.g., rods 6 and 7 are coupled to an electricmotor 21 that has mechanical means for rapidly reciprocating the rods 6and 7 such that they travel in straight trajectories, each alternatingfrom a proximal to distal direction. More specifically, when thesuperior rod 6 is being pushed in a distal direction, the inferior rod 7is simultaneously being pulled in a proximal direction, and vice versa.Preferably the motor 21 is positioned at the proximal end of the device1 and is operably coupled to the proximal ends, or substantially so, ofthe extension members, e.g., rods 6 and 7. An alternative is to have themotor be a stand-alone unit, separate from the instrument and attachedto the reciprocating gear system via a cable. A power control, such as aswitch 22, operably coupled to a power source (e.g., batteries,electrical plug) can be used to turn the motor 21 on and off. A dial,not shown, can also be used to adjust the motor 21 to control thereciprocation speed of the extension members, e.g., rods 6 and 7.

Depending on the blade shape, a crossbar 8 may or may not be used withthe embodiments described herein. For oval shaped blades 4 and 5, shownin FIG. 5A, it is preferred that the crossbars 8 and 9 are not used, andthat the outer blades couple directly to the ends of the extensionmembers 6 and 7. For these embodiments, while parallel, the extensionmembers 6 and 7 are preferably staggered or offset from each otherslightly in opposite directions at their distal ends, in the left/rightplane, by 1 mm or less. The offset can be in the form of flares 32 and33 (FIG. 5A) or cutouts 34 and 35 (FIG. 5B). The offset only can beslight, such as the thickness of the blades 4 and 5, and is incorporatedso that the blades 4 and 5 don't interfere with each other as theyreciprocate. For example, and as shown in FIGS. 1, 2, 3, and 5A thedistal end 32 of the superior rod 6 is flared to the left, while thedistal end 33 of the inferior rod 7 is flared to the right. Similarly asshown in FIG. 5B, the left distal end of the superior rod is cutout 34and the right distal end of the inferior rod is cutout 33. The flares 32and 33 or cutouts 34 and 35 are preferably offset the same lateraldistance (e.g., 1 mm or less). The flares 32 and 33 should not be flaredtoo wide in the left/right lateral plane that they cannot fit within thedistal opening 10 of the external tube 3, when the blades 4 and 5 areretracted within. As in the rods, it is preferred that the distal endsof the ribbons 6′ and 7′ are offset from each other with flares 32 and33 in the right/left plane.

FIG. 5A shows how the oval blades 4 and 5 couple to the distal ends oftheir extension members 6 and 7. The outer blade 4 comprises a left end23 coupled to the flared left end 32 of the superior extension member 6and a right end 24 coupled to the right flared end 33 of the inferiorextension member 7. Similarly, the inner blade 5 comprises a left end 25coupled to the non-flared left end of the inferior extension member 7and a right end 26 coupled to the non-flared right end of the superiorextension member 6. With respect to FIG. 5B, the outer blade's 4 leftend 23 couples to the non-cutout left end of the superior extensionmember 6 and the right end 24 couples to the non-cutout right end of theinferior extension member 7. Similarly, the inner blade's 5 left end 25couples to the cutout left end 34 of the inferior extension member 7 andthe right end 26 couples to the cutout right end 35 of the superiorextension member 6.

In contrast, for U-shaped blades 4′ and 5′, shown in FIGS. 4A and 4B, itis preferred that a superior and inferior crossbars 8 and 9 are attachedto the distal ends of their respective extension member 6 and 7. Whencrossbars are used, a superior crossbar 8 is positioned perpendicular toand at the distal end of the superior extension member 6. Preferably,the superior extension member 6 couples to the superior crossbar 8 nearthe middle, offset by less than 1 mm in one direction, of the crossbar8. Similarly, an inferior crossbar 9 is positioned perpendicular to andat the distal end of the inferior extension member 7. Preferably, theinferior extension member 7 couples to the inferior crossbar 9 near themiddle, offset in the opposite direction by less than 1 mm, of thecrossbar 9. It is preferred that the coupling between the crossbars 8and 9 with their respective rods 6 and 7 is a fixed coupling thatdoesn't allow the crossbars 8 and 9 to rotate around the rods 6 and 7during operation. The crossbars 8 and 9 are configured to alternatetraveling in the proximal/distal directions with their respectiveextension members 6 and 7.

It is advantageous to have the crossbars 8 and 9 be the same length orsubstantially so. The superior and inferior crossbars 8 and 9 areparallel to each other, and individually have left (14 and 16) and right(15 and 17) ends. It is preferred that the crossbars 8 and 9 are offsetleft to right the same distance, and as shown in the cross-section viewof FIGS. 6 and 7. While the superior crossbar 8 is shown extendingfarther left than the inferior crossbar 9, these offsets can readily beinterchanged such that the inferior crossbar 9 extends farther rightthan the superior crossbar 8. For these embodiments, while parallel andthe same length, the cross bars 8 and 9 are preferably staggered oroffset from each other slightly in opposite directions in the left/rightplane by 1 mm or less. The offset can be slight, such as the thicknessof the blades 4′ and 5′, and is incorporated so that the blades 4′ and5′ don't interfere with each other as they reciprocate.

With reference to FIGS. 4A and 4B, the outer U-shaped blade 4′ comprisesa left end 23 coupled to the left end 14 of the superior crossbar 8 anda right end 24 coupled to the right end 17 of the inferior crossbar 9.Similarly, the inner U-shaped blade 5′ comprises a left end 25 coupledto the left end 16 of the inferior crossbar 9 and a right end 26 coupledto the right end 15 of the superior crossbar 8. FIGS. 6 and 7 illustratestraightened and detached views of the outer blade 4′ and the innerblade 5′ in context with their coupling points 14-17 on the crossbars 8and 9. As shown in this view, the outer blade 4 is preferably longerthan the inner blade 5 (e.g., 1-3 mm longer, for example), as ittraverses a longer distance in connecting the outer ends 17 and 14 ofthe crossbars 8 and 9, in contrast to the inner blade 5 which traversesa shorter distance in connecting the inner ends 15 and 16 of thecrossbars 8 and 9. Thus when in the loop configuration, such as shown inFIGS. 4A, 4B and 5A, 5B, the outer blade 4 has a slightly largerdiameter than the inner blade 5. The blades 4 and 5 preferably touch,but glide past each other when cutting.

Blades described herein 4′ and 5′ can have side extensions 23-26, thatare shown in FIGS. 6-10 for example. FIG. 7, shows an embodiment wherethe inner blade 5′ has extensions 25 and 26 but the outer blade 4′ lacksextensions and just has a left end 23′ and right end 24′. Extensions areused herein because while the blades cross over from one extensionmember (crossbar) to another, they remain in the same plane and parallelto each other. Without the extensions 25 and 26 the inner blade 5′ wouldcollide with the flared distal ends 32 and 33 of the extension members 6and 7, or the ends of the crossbars 8 and 9 that attach to the outerblade 4. Either the blade ends 23′ 24′ or extensions 23-26 of the bladescan couple to the extension members 6 and 7 or crossbars 8 and 9 insimilar ways. The height of the blade ends 23′ 24′ or extensions 23-26is preferably the same width as the thickness of the distal ends of theextension members, e.g., rods, crossbars. If the inner blade 5 has bladeends 23′ 24′ or extensions 23-26 wider than the thickness of the distalends of an extension member 6 or 7 then it could potentially collidewith the other extension member 6 or 7 during operation. For example, ifthe extension member's distal ends (where they couple to the blade ends23′ 24′ or extensions 23-26) are 4 mm wide then they each can be 2 mmthick and still slide through the 8 mm external tube. Therefore thewidth of the blade ends 23′ 24′ or extensions 23-26 can be 2 mm inwidth. The length of the extensions 23-26 is preferably equivalent tothe distance traveled by the blade. Thus if the blade 5′ was travelingback and forth 12 mm, during the reciprocating cutting, the leftextension 25 would be 12 mm and the right extension 26 would be 12 mm.The above applies likewise for the outer blade 4′. Preferred travel ofthe blades is greater than 10 mm.

Alternatively, and as shown in FIGS. 31 and 32, additional embodimentsherein are directed to the use of extension members 6 and 7 havingdistal segmental cutouts 34 and 35. The cutouts 34 and 35 are positionedon the opposite lateral side of their respective extension member 6 and7 from each other. Each cutout 6 and 7 has a distal-proximal length 340and 342 that is substantially the same as the reciprocating length ofthe extension members 6 and 7 as they travel distally and proximally.This configuration prevents undesired collisions of blades 4″ or 5″ andextension members 6 and 7. The first end section 140′ of the outerlooped blade 4″ couples to a section of the inferior extension member 7that is proximal to the cutout 35, preferably adjacent to the cutout 35,while the second end section 138′ of the outer looped blade 4″ couplesto a section of the superior extension member 6 that is proximal to thecutout 34, preferably adjacent to the cutout 34. The first end section134′ of the inner looped blade 5″ couples to a section of the superiorextension member 6, that is on the opposite lateral side of the cutout34, preferably at the distal end of the extension member 6, while thesecond end section 136′ of the inner looped blade 5″ couples to asection of inferior extension member 7, that is on the opposite lateralside of the cutout 35, preferably at the distal end of the extensionmember 7. The coupling of the blades 4″ and 5″ to the extension members6 and 7 can be done through any suitable ways, non-exclusively includingwelding, rivets, adhesives, and the like. The extension members 6 and 7for this embodiment, can have a greater thickness, than the tabbedextension members, shown as ribbons, e.g., 100 and 102.

According to these cutout embodiments, it is preferred that the blades4″ and 5″ are the same width throughout and don't require slits.Specifically, the blades can lack narrow extensions (e.g., 25 and 26) onthe ends.

The extension members can also be narrow ribbons having tabs configuredto operably couple with slits within the outer and inner looped blades.For example, FIG. 20 is a plan view of a straightened outer looped blade130 with slits, and a straightened inner looped blade 132 with slits.FIGS. 21 and 22 show extension members 100 and 102 and 100′ and 102′with tabs configured to fit within the slits of the inner and outerlooped blades.

As shown in FIG. 20 the slotted outer looped blade 130 is longer thanthe slotted inner looped blade 132. The following description of slitsis merely exemplary. More or less slits, and different shapes of slitscan be utilized other than those shown depending on the number and shapeof corresponding tabs on the extension members. The outer slotted loopedblade 130 has a first end section 140 having a longer slit 122 and ashorter slit 124. The second end section 138 of the outer slotted loopedblade 130 also has a longer slit 120 and a shorter slit 118. The longerslits 122 and 120 are preferably of a length that allows thecorresponding tabs within them to reciprocate distally and proximallywithout hitting the ends of the longer slits 122 and 120. The innerlooped blades has a first end section 134 having a slit 128, which canbe substantially the same length as the shorter slits 124 and 118 of theouter looped blade 130.

In FIG. 21, the main body of the ribbon extension members 100 and 102 isin general flat, with a minimal thickness of less than 2 mm. The distalend section 142 of the superior extension member 100 narrows at a neck114 and includes a distally positioned tab 108 that extends to the rightand a proximally positioned tab 106 that extends in the oppositedirection (left) of the distally positioned tab 108. Likewise, thedistal end section 144 of the inferior extension member 102 narrows at aneck 116 and includes a distally positioned tab 110 that extends to theleft and a proximally positioned tab 116 that extends in the oppositedirection (right) of the distally positioned tab 110. The left/rightorientations of the proximally and distally positioned tabs can also beswitched.

FIG. 22, shows a slightly different variation of the extension membersof FIG. 21. The main body of the extension members 100′ and 102′ is ingeneral flat, with a minimal thickness of less than 2 mm. The distal endsection 142′ of the superior extension member 100′ splits into twoprongs 119 and 121, both of which are narrower than the main body. Thefirst prong 119 includes a distally positioned tab 108′ that extends tothe right and the second prong 121 includes a proximally positioned tab106′ that extends in the opposite direction (left) of the distallypositioned tab 108′. Likewise, the distal end section 144′ of theinferior extension member splits into two prongs 123 and 125, both ofwhich are narrower than the main body. The first prong 125 includes adistally positioned tab 110′ that extends to the left and the secondprong 123 includes a proximally positioned tab 112′ that extends in theopposite direction (right) of the distally positioned tab 110′. Theleft/right orientations of the proximally and distally positioned tabscan also be switched.

FIGS. 23-25 show how the tabs of the extension members, housed within aninner tube 2 interact with the slits of the outer and inner loopedblades. As shown, the distally positioned tab 108 of the superiorextension member 100 is first inserted into the slit 128 of the firstend section 134 of the slotted inner looped blade 132. Likewise, thedistally positioned tab 110 of the inferior extension member 102 isfirst inserted into the slit 126 of the second end section 136 of theslotted inner looped blade 132. The distally positioned tab 108 of thesuperior extension member 100 is inserted into the longer slit 122 ofthe first end section 140 of the slotted outer looped blade 130. Theproximally positioned tab 112 of the inferior extension member 102 isinserted into the shorter slit 124 of the first end section 140 of theslotted outer looped blade 130. Similarly, the distally positioned tab110 of the inferior extension member 102 is inserted into the longerslit 120 of the second end section 138 of the slotted outer looped blade130. The proximally positioned tab 106 of the superior extension member100 is inserted into the shorter slit 118 of the second end section 138of the slotted outer looped blade 130. The longer slits 122 and 120 ofthe outer looped blade 130 can have a length substantially equal to thereciprocating length of the extension members 100 and 102 duringoperation, such that the distally positioned tabs 108 and 110 of thefirst and second extension members 100 and 102 slide within theirrespective longer slits 122 and 120 of the slotted outer looped blade130 without contacting the ends of the longer slits.

The pronged flat extension members 100′ and 102′ can readily besubstituted for the above described flat extension members 100 and 102,wherein the tabs 106′, 108′, 110′, and 112′ are respectively substitutedfor tabs 106, 108, 110, and 112 and inserted into the same slots. Theseparate prongs 119, 121 and 123, 125 of the first and second extensionmembers 100′ and 102′ have different lengths to prevent collision duringoperation.

In still further embodiments the position of the looped blade 132 isinterchangeable with looped blade 130, such that the looped blade 132(with 2 slits: 126 and 128) can be positioned on the outside of thelooped blade 130 (with 4 slits: 118, 120, 122, and 124) can bepositioned on the inside of the looped blade 132. This interchangedembodiment with respective tab coupling is shown in FIGS. 27 and 28 andcan likewise correspond to the respective tabs (106′, 108′, 110′, and112′) of the pronged extension members 100′ and 102′.

In further embodiments, and as shown in FIG. 29, an inner tube 2′ cansheath the outer and inner looped blades 130 and 132 at their first andsecond end sections 134, 136, 138, and 140 and therefore be used tostabilize and/or prevent the tabs from disengaging from the slits duringmotion.

Various configurations can be used to create channels within the innertube 2 configured to guide the substantially flat extension members 100,102 and 100′, 102′ so they can remain on the desired plane duringmotion. The purpose of these channels is to prevent undesired bending orfolding of the extension members 100, 102 and 100′, 102′ and theoperably coupled blades 130 and 132 during operation. For example, FIGS.23, 24, 27 and 28 show internal tabs 150 that create channels within theinner tube 2 and are configured to keep the extension members 100 and102 within the same plane during proximal and distal reciprocation.Alternatively, instead of tabs 150, indentations or grooves within theinner surface of the inner tube 2 can function as alternative channelsto guide the extension members. A further alternative, as shown in FIG.25 can utilize extension members 146 and 148 that have a semicylindricalshape and fit snugly within the inner tube 2 to keep them within thedesired plane of motion. In this embodiment the flat distal end sections142, 142′, 144, and 144′ can be the same as shown in the flat extensionmembers 100, 100′, 102′, and 102′. Any other suitable configurations canbe used to stabilize the extension members and blades such as fillingthe inside of the inner tube with low friction material, such as tefloncoated rods positioned on the same axis as the tube, to create a closefit with the reciprocating extension members and limiting the amount ofspace that they can travel off plane.

In the interested of expediency the inner and outer tubes have beendescribed and shown as cylindrical. However, any suitable shape can beused and interchanged with the embodiments described herein. Exemplarytubes can non-exclusively include: square, elliptical, or hexagonalcross-sectional shapes.

When cutting there is counter traction by the tissue on the blades 4 and5. Left alone, this counter traction could potentially result in oneblade being pushed inferior to the other blade during cutting. Thiswould undesirably result in a separation of the sharp edges (e.g.,superior edges) from the same plane, such that the inferiorly pushedblade no longer contacts the targeted tissue, thereby making itineffective. FIGS. 9 and 10 show straightened views of blades 4 and 5with back stops 42 and 43 that are designed to prevent the aboveconcern. These backstops 42 and 43 are small extensions, one backstop 42is positioned mid-lateral, on the inferior end of the inner blade 5 andthe other backstop 43 is positioned on the opposite side, mid-lateral,on the inferior end of the outer blade 4. The blade opposite thebackstops 42 and 43 has been cut slightly shorter at its inferior end,so that it can glide over the backstop. This cut out segment is at leastthe length of the distance traveled by the extension members 6 and 7.During operation, the cut out segment 45 of the inner blade 4 slidesover the backstop 42 of the outer blade 5. Similarly the cut out segment44 of outer blade 5 slides over the backstop 43 of the inner blade 4.

As the blades 4 and 5 described herein individually complete a loop, itis preferred that they are made of a sufficiently flexible material thatalso has sufficient strength for cutting through targeted tissue. Thiscan include flexible thin metals (less than 1 mm thick, such as between0.5-1 mm.) such as nickel titanium, also known as nitinol. Additionallythe blades 4 and 5 can be made of a metal alloy, or suitable compositematerials such as carbon fiber, for example. The devices 1 herein aredesigned to use the edge of the blades 4 and 5 for cutting, so it ispreferred that the blades have at least one edge configured to cut intotissue, but preferably it is the superior edges of the blades. Thecutting edge or edges of the blades 4 and 5 can be smooth or serrated.According to other embodiments designed to prevent the blades frommoving off plane a slider mechanism similar to that used in FIGS. 13 and19 can be used. According to this embodiment, either the outer or innerlooped blade has a pin, and the other looped blade has a slot configuredto keep the blades together and allow the pin to reciprocate within theslot, as the blades move in clockwise and counter-clockwise directions.Preferably the pin and slot are positioned at the most distal end of thelooped blades. The slot length is at least equal to or longer than thestroke length of the extension members.

Preferred blades 4 and 5 described herein, are configured to cutcylindrical shaped tissue, or substantially so of a predeterminedthickness, to fit through a trocar sleeve of a predetermined diameter.The blades 4 and 5 can be looped to shapes including: circular,omega-shaped (Ω), oval, square, U-shaped, or substantially similarvariants. Preferred blades have curved sides and lack straight sides,and angles of 120 degrees or less, accordingly V-shaped or polygonshaped blades (e.g., squares, rectangles, hexagons rhombuses) are notpreferred. It is preferred that both blades 4 and 5 are configured intothe same shape, with the inner blade 5 being slightly shorter than theouter blade 4. FIGS. 4A and 4B illustrate a U-shape configuration ofblades 4′ and 5′ while oval shaped blades 4 and 5 are shown in FIG. 5A.These shapes both are collapsible, are interchangeable with one anotherand with other suitable shapes for all embodiments herein, whereapplicable. The U-shape blades 4′ and 5′ are advantageous forembodiments wherein the crossbars 8 and 9 are used, while the ovalshaped blades 4 and 5 are suited for embodiments wherein the crossbars 8and 9 are not used, and the blades 4 and 5 are configured to collapsewithin the external tube 3 when they make contact with distal rimsurrounding the opening 10.

Preferably the ends of the blades 4 and 5 are configured to releasablyattach to the crossbars 8 and 9 to make replacement of dull bladespossible during operation, without having to replace the entireinstrument. Any suitable releasable attachment means can be used for theblades 4 and 5 and the crossbars 8 and 9, including snaps, pins, slots,notches, tabs, locks, and the like. According to other embodiments, theblades 4 and 5 can be non-releasably attached to the crossbars 8 and 9,which are releasably attached to the rods 6 and 7, to allow for changingout new blades 4 and 5. Still further preferred embodiments relate toblades being non-releasably attached to crossbars, wherein the crossbarsare non-releasably attached to the distal end of the rods, and theproximal ends of the rods are releasably attachable to the device, sothat a user would change out old blades with a new rod/crossbar/bladeassembly being inserted into the internal tube 2 and/or the externaltube 3.

As mentioned above, the rods 6 and 7 are configured with the motor 21 toreciprocate rapidly back in forth in proximal and distal directions.This motion causes the blades 4′ and 5′ to oscillate such that one end(left/right) of a blade is being pulled proximally while the oppositeend (left/right) of the same blade is being pushed distally. FIGS. 4Aand 4B show how the reciprocating rods 6 and 7 cause the blades 4′ and5′ to saw back and forth. In FIG. 4A, the superior rod 6 is pushing thesuperior crossbar 8 distally. This motion pushes the outer blade 4′ in aclockwise direction, and pushes the inner blade 5′ in acounter-clockwise direction. Simultaneously in FIG. 4A, the inferior rod7 is pulling the inferior crossbar 9 proximally. This motion pulls theouter blade 4′ in a clockwise direction, and pulls the inner blade 5′ ina counter-clockwise direction. In FIG. 4B, the directional motions shownin 4A are reversed, such that the superior rod 6 is pulling the superiorcrossbar 8 proximally. This motion pulls the outer blade 4′ in acounter-clockwise direction, and pulls the inner blade 5′ in a clockwisedirection. Simultaneously in FIG. 4B, the inferior rod 7 is pushing theinferior crossbar 9 distally. This motion pushes the outer blade 4′ in acounter-clockwise direction, and pushes the inner blade 5′ in aclockwise direction. Accordingly, the outer blade 4′ and the inner blade5′ alternate between being pushed and pulled, where the outer blade 4′cuts in one rotational direction, while the inner blade 5′simultaneously cuts in an opposite rotational direction. This motion issimilar for embodiments where crossbars are not used.

Preferred devices 1 described herein are configured such that theexternal tube 3 traverses along the same axis as the internal tube 2that is fixed to the handle and positioned within the external tube 3.According to preferred embodiments, the looped blades 4 and 5 have alarger diameter than the distal opening 10 and are configured tocollapse when the external tube 3 is pushed into its most distalposition, as shown in FIG. 1. For embodiments shown in FIGS. 4A and 4B,the crossbars 8 and 9 have a longer length, from their left and rightends 14 to 15, and 16 to 17, than the diameter of the external tube 3and are configured such that they can be collapsed/retracted into andopened/extended outward from a distal opening 10 of the external tube 3.Two preferred embodiments of retracting the crossbars 8 and 9 are shownin FIGS. 15-16 and FIGS. 17-18.

The collapsing of the blades 4 and 5 is shown in FIGS. 1-3. Whilecrossbars are not shown in these figures, collapsible crossbars can beused with the same mechanisms described. Preferably, a tube spring 19 ispositioned proximal to and operably coupled with the coaxial externaltube 3. FIG. 1 illustrates the device 1 in its' neutral or closedposition, where the tube spring 19 is in a fully uncompressed state. Inthis natural position, the external tube 3 is pushed forward to itsmaximum distal distance and thereby encloses the blades 4 and 5, eitherentirely or partially. In this state, the blades 4 and 5 are preferablycompressed within the external tube 3, in comparison to their expandedstate outside of the external tube 3.

A handle 18 (with or without a handle spring 20) can be operably coupledto the external tube 3 such that squeezing the handle 18 slides theexternal tube 3 in a proximal direction, thereby compressing the tubespring 19. Other suitable handle and/or trigger configurations can beused to manipulate the external tube 3 in distal and proximal directionsas well. FIG. 2 illustrates the device 2 in a partially compressedstate, with the handle 18 being partially squeezed, thereby moving theexternal tube 3 in a proximal direction, and thereby partiallycompressing the tube spring 19. The proximal sliding of the externaltube 3 allows the distal end of the internal tube 2 and the blades 4 and5 to be exposed from the external tube's opening 10. For crossbars (notshown) they would be extended distally outward from the external tube'sopening 10 as well. Once released from the external tube 3, the flexibleblades 4 and 5 can spring into their uncompressed looped or operationalconfigurations, such as shown in FIGS. 2, 4A, 4B, and 5A, for example.

Preferred devices 1 described herein have a bendable neck 11 positionedon the internal tube 2 near the distal end, but proximal to thecrossbars 8 and 9 and blades 4 and 5. The bendable neck 11 allows forthe internal tube 2 to articulate in the superior direction, as shown inFIG. 3. Preferred a angles of full articulation include 30-45°, forexample. The blades 4 and 5 are preferably perpendicular to the tissuebeing cut. The blades 4 and 5 may first need to be in a straightconfiguration (e.g., FIG. 2) to cut into the targeted tissue. As it cutsdeeper into the tissue the sharp end (e.g., superior edge of the blades4 and 5) is rotated proximally by bending the distal end as shown inFIG. 3. However as a user pulls the device 1 proximal the blades 4 and 5continuously straighten out. This can be accomplished by straighteningout the bendable neck 11 or by pivoting at the point of insertion of thetrocar sleeve into the body. The bendable neck 11 is also advantageousin preventing the device 1 from getting jammed in the tissue or thehandle 18 from hitting the side of the table or abdominal wall. Also itis more ergonomic for the user to be able to bend the neck 11 bysqueezing the handle 18, keeping the wrist and arm in a more neutralposition.

The bendable neck 11 can be similar to articulating necks described inU.S. Pat. No. 8,585,727 “Tissue Severing Devices and Methods” inparticular: FIGS. 25 and 26 and descriptions thereof. This reference isexpressly incorporated by reference herein in its entirety. Suitablemechanisms to allow for superior articulation may include, but notlimited to, one or more pivots, joints (e.g., bellows joint), extensibletubing, distal bendable ribbon segments, and rigid segments coupled byflexible or elastic interconnects. As discussed previously, the tworeciprocating rods 6 and 7 positioned inside of the internal tube 2 arealso bendable either in their entireties or within their neck regionsthat are positioned within the bendable neck 11 of the internal tube 2.According to one preferred embodiment, as a bellow joint 11 bends, theinner rods 6 and 7 are forced to bend yet can still continue theirreciprocating motion during operation. Thus the rods 6 and 7 can bedesigned such that they can reciprocate in a straight or curvedconfiguration. Alternatively, (not shown) the bendable neck 11 comprisestwo or more segments that are interconnected by a pivot joint. In yetanother embodiment (not shown) the internal tube can be bendable,incorporating the bendable reciprocating extension members (rods). Inthis embodiment, the bendable joints are not necessary and the internaltube with rods would bow to the desired angle. Alternatively, the rigidinternal tube can have a flexible extension on its inferior endextending distally and inferior to the reciprocating rods. An arc orloop is fixed to the most distal end of the flexible extension andextends superiorly. A pull ribbon can be fixed to the top (superior end)of the arc or loop. The reciprocating ribbons continue from inside theinner tube over an extension ribbon over the flexible extension segmentof the internal tube through the inside of the arc, where they then arefixed to the crossbars attached to the blades. Pulling the pull ribbonas described above bends the extension segment and the reciprocatingribbons that are stacked above it.

Any suitable apparatus can be used for articulating the bendable neck11. As a non-exclusive example, a bendable pull ribbon 12 or cable canbe fixed to the superior, distal end of the internal tube 2. The pullribbon 12 is preferably coaxial with the internal tube 2 and traversesin a proximal/distal direction between the external tube 3 and theinternal tube 2. Preferably, the pull ribbon 12 is not fixed to theproximal area of the internal tube 2 and has a floating catch 13positioned at its most proximal end, preferably extending upwards. Asshown in FIG. 2, when the external tube 3 is pulled proximallypartially, the blades 4 and 5 are first released from inside theexternal tube 3. With further squeezing of the handle 18, the proximalend of the external tube 3 is further pulled proximally and engages withthe catch 13 on the pull ribbon 12 thereby pulling the pull ribbon 12further proximal. As shown in FIG. 3, this results in pulling of thedistal end of the internal tube 2 and bending the neck 11 in a superiordirection. The further the pull ribbon 12 gets pulled proximally, themore acute the α° angle of the neck 11. FIG. 3, shows the device 1 in afully compressed configuration, wherein the tube spring 19 is fullycompressed, the handle 18 (and handle spring 20) is maximally squeezed,the external tube 3 is in its furthest proximal position, and the neck11 of the internal tube 2 is articulated at its limit. Both the tubespring 19 and/or the handle spring 20 can be used according with theembodiments herein. The rods 6 and 7 and coupled blades 4 and 5 areconfigured to rapidly reciprocate in any position (straight or curved)shown in FIGS. 1-3, or positions in between. In an alternative designnot shown, each of the rods, near the distal end, has a segment that isbent to about 25 degrees in it neutral position. The outer tubestraightens the rod when pushed distally over the bent segment. When theouter tube is pulled proximally exposing this segment, the rods bendtoward their neutral position. In this design, the pull ribbon is usedto stabilize the bend as counter traction during operation.

When the handle 18 is released from a squeezed/compressed position shownin FIG. 3, the tube spring 19 pushes the external tube 3 distally. Ifthe release is partial, the neck 11 straightens as the device 1 returnsto the configuration shown in FIGS. 2 and 11. If the release iscomplete, the tube spring 19 pushes the external tube 3 to its maximaldistal position, as shown in FIG. 1. During this release, it ispreferred that the external tube 3 slides forward collapsing theflexible blades 4 and 5 so that they can fit inside the distal opening10 of the external tube 3. Oval shaped blades 4 and 5 are preferred forthis embodiment, as they do not require collapsible cross bars as do theU-shaped blades 4′ and 5′. Otherwise for the U-shaped blades attached tothe non-collapsible cross bars, the external tube 3 along with theenclosed collapsed blades 4 and 6 can be inserted or removed through atrocar sleeve having a larger diameter (not shown), of larger diameterthan the length of the cross bars.

Alternatively, the device can be configured to such that the externaltube 3 can collapse the crossbars 8 and 9 and the attached U-shapedblades 4′ and 5′. One non-exclusive method of collapsing the crossbars 8and 9 is to have them made of a bendable material (e.g., fiberglass,thin metal, such as stainless steel, spring steel, or nitinol).According to this embodiment, and as shown in FIGS. 17 and 18, thecrossbars 8 and 9 are forced to bend distally at its point of fixation41 with the reciprocating extension members 6 and 7 as the outer tube 3is pushed distally. A spring 40 can be positioned between the ends ofthe crossbar 8 to help maintain its open shape when exposed outside ofthe external tube 3.

Another way to collapse the U shaped blades 4′ and 5′ is to have thecrossbars 8 and 9 swivel in one direction as the external tube is pusheddistally, coming in contact with the crossbars. To accomplish thisfunction, and as shown in FIGS. 15 and 16, the distal end of theexternal tube 3 can be beveled, such that the distal end of the bevel 36comes in contact with one side of the crossbars 8 and 9 to collapse it.For example, if the crossbar is configured to swivel clockwise then thebevel is on the distal left of the external tube and if the crossbar 8swivels counterclockwise (shown in FIGS. 15 and 16) then the bevel 36 inon the distal right of the external tube. As the external tube 3 movesdistally, the bevel end 36 hits the right side 15 of the superiorcrossbar 8, thus pushing the left end 14 of the crossbar 8 proximally.Suitable springs can be used to allow for the crossbar 8 to collapsewithin the external tube 3 and expand perpendicularly to the extensionmembers 6 and 7 after being released from the external tube 3 and remainrigid for operation. For example, a torsion spring 38 is positionedbetween the left end 14 of the crossbar 8 and the superior extensionmember 6 and a tension spring 39 is positioned between the right end 15of the crossbar 8 and the superior extension member 6. While only onesuperior crossbar 8 is shown in FIGS. 15 and 16, the inferior crossbarcan operate in the same way.

During cutting, the swiveling crossbars 8 and 9, should be locked in afixed position perpendicular to the rods 6 and 7, so that the crossbars8 and 9 can move with the rods. One way to lock the crossbars in a fixedposition, is for a central ratcheted pin 37 that attaches the crossbars8 and 9 to the distal end of the extension members 6 and 7 that has akeeps the cross bars stationary during operation and/or can have alocking mechanism on it.

Alternatively, certain devices herein are not configured to bendupwards, such as shown in FIG. 19. According to these simplifiedembodiments, an internal tube is not utilized, nor are pull ribbons,catches, or bendable necks. The extension members 6′ and 7′ can beribbons or rods, and can be rigid, without the ability to bendsignificantly. In this embodiment, only one tube can be used to collapseand release the blades and the crossbars. As shown in FIG. 29, the sametube can also sheath and stabilize the looped blades 130 and 132 attheir first and second end sections 134, 136, 138, and 140 and thereforebe used to prevent the tabs from disengaging from the slits duringmotion. According to further embodiments, the tube can be adjusteddistally and proximally to respectively decrease and increase the sizesof the looped blades and therefore cut smaller or larger diameter tissuepieces, as desired by the user.

According to preferred embodiments and as shown in FIG. 15, a catchingbag 27 can be positioned below the blades 4 and 5. Preferably the bag 27is coupled to the outside blade 4 using any suitable means such as glue,solder, or rivets. This embodiment may be advantageous in helping toprevent cut up pieces of tissue from contaminating surrounding areas.The bag 27 catches severed tissue after it is cut away by the blades 4and 5. It is preferred that the bag 27 is elastic as it will distortwith the reciprocating motion of the blades 4 and 5. Preferably the bag27 is made of a solid, elastic material throughout, without holes, suchas rubber, nylon, and the like.

FIG. 26 is a perspective view of dual blade cutting device with atorsion spring 300 that is operably coupled to anterior and posteriorextensions (302 and 304) of an immobile inner tube 2. The torsion spring300 has two purposes, the first is to help stabilize the outer and innerlooped blades (132 and 130) during motion by preventing them fromangulating off plane. The second purpose is that the torsion spring 300acts as a backstop to keep tissue from getting trapped near the distalend of the inner tube 2 during cutting. The torsion spring 300 can beattached to the distal end of the inner tube 2 by any suitableconfiguration. As one non-limiting example, a pin 306 can traversethrough a pinhole within the center of the torsion spring 300 andoperably couple to the anterior and posterior extensions 302 and 304.The torsions spring 300 is coupled to first and second wings 308 and 310that extend distally and laterally and are positioned against the insidesurface of the inner looped blade 132. For embodiments where the innerlooped blade 132 is interchanged with the outer looped bade 130, thewings 308 and 310 would be positioned against the inside surface of theouter looped blade 130, as shown in FIG. 28. The wings 302 and 304 canbe any suitable shape, but are preferably flaps that are as tall, or atleast ½ or ¼ of the height of the outer and inner looped blades 130 and132. During operation of the cutting device, the looped blades 132 and130 reciprocate distally and proximally while the wings 302 and 304remain static. Additional embodiments, as shown in FIG. 30 allow thecutting device to collapse the blades 130 and 132 and wings 302 and 304,such as a third or external tube 3′ that slides or telescopes over theblades 130 and 132 and wings 302 and 304 to collapse them both andreleases them when pulled back. The external tube 3′ can be configuredto move distally over the blades 130 and 132 and torsion spring 300collapsing them for insertion and removal. The external tube 3′ can thenbe moved back proximally to release the blades 130 and 132 and spring300, during operation. The immobile inner tube 3 can be utilized to trapthe tabs 106, 108, 110, and 112 and operably coupled looped blades 130and 132 and to help stabilize the extension members 100 and 102 duringoperation.

The cutting devices 1 described herein, having dual looped blades 4 and5 that simultaneously move in opposite directions is highly advantageousover the prior art. The embodiments herein allow for increased travelback and forth compared to a single looped bladeolo, as the two blades 4and 5 are now simultaneously cutting in opposing rotational directions.The dual blades 4 and 5 also helps prevent the targeted tissue frommoving in the same direction as the cutting path of an oscillatingsingle looped blade. Reciprocating looped blades 4 and 5 simultaneouslymoving in opposing rotational directions helps stabilize the designatedarea so that the cutting edges of the blades 4 and 5 can make purchasewith the tissue. Experiments done with double looped blades moving inthe same direction was found to be disadvantageous in that the bladestended to bend at the neck of the loop. Configuring the devices hereinsuch that the double blades move simultaneously in opposite directions(clockwise and counter-clockwise) helps to prevent this undesiredbending of the blades as the rods reciprocate in opposite directions.This beneficial stabilizing effect results from a more fluid motion ofthe blades moving back and forth in opposing directions along theircontour.

Any suitable materials can be used to make the assemblies 1 describedherein including plastics and metals. The invention may be embodied inother specific forms besides and beyond those described herein. Theforegoing embodiments are therefore to be considered in all respectsillustrative rather than limiting, and the scope of the invention isdefined and limited only by the appended claims and their equivalents,rather than by the foregoing description.

The invention claimed is:
 1. A tissue cutting device comprising: anelectric motor configured to be turned on and off; a first tube havingan internal channel traversing lengthwise from proximal to distal ends;first and second extension members having proximal and distal ends, leftand right sides, and positioned superiorly and inferiorly to one anotherwithin the internal channel of such that they traverse parallel with thelength of the tube, wherein the proximal ends of the extension membersare operably coupled to the electric motor that drives straightreciprocating motion of the first and second extension members inalternate proximal and distal directions with respect to each other,such that when the first extension member is pushed distally the secondextension member is pulled proximally, and vice versa; an outer loopedblade having a first end section operably coupled to first extensionmember; and a second end section operably coupled to the secondextension member; and an inner looped blade, positioned proximally andadjacent to the outer looped blade, and having a first end sectionoperably coupled to the second extension member and a second end sectionoperably coupled to the first extension member; wherein the outer andinner looped blades are positioned distally to the distal end of theexternal tube, and configured to reciprocate in alternate clockwise andcounter-clockwise directions and in opposite directions with respect toeach other as the first and second extension members reciprocateproximally and distally, and wherein, the first and second end sectionsof the outer and inner looped blades have slits, and wherein the firstand second extension members have tabs that are configured to beinserted into, and thus operably couple to, the slits on the outer andinner looped blades and the first extension member has a distal endsection having a distally positioned tab that extends to the right orleft and a proximally positioned tab that extends in the oppositedirection of the distally positioned tab, and the second extensionmember has a distal end section having a distally positioned tab thatextends to the right or left and opposite the corresponding distal tabof the first extension member, and has a proximally positioned tab thatextends in the opposite direction of the distally positioned tab.
 2. Thetissue cutting device of claim 1, wherein the first end section of theouter looped blade comprises a longer slit and a shorter slit, and thedistally positioned tab of the first extension member is inserted intothe longer slit, and the proximally positioned tab of the secondextension member is inserted into the shorter slit; and wherein thesecond end section of the outer looped blade comprises a longer slit anda shorter second slit, and the distally positioned tab of the secondextension member is inserted into the longer slit, and the proximallypositioned tab of the first extension member is inserted into theshorter slit.
 3. The tissue cutting device of claim 2, wherein the firstend section of the inner looped blade comprises a slit, that thedistally positioned tab of the first extension member is inserted into,and wherein the second end section of the inner looped blade comprises aslit, that the distally positioned tab of the second extension member isinserted into.
 4. The tissue cutting device of claim 2, wherein thedistally positioned tabs of the first and second extension members cantravel proximally and distally within their respective longer slits. 5.The tissue cutting device of claim 4, wherein the longer slits of theouter looped blade have a length substantially equal to thereciprocating length of the extension members during operation, suchthat the distally positioned tabs of the first and second extensionmembers slide within their respective longer slits of the blade withoutcontacting the ends of the longer slits.
 6. The tissue cutting device ofclaim 1, wherein the first end section of the inner looped bladecomprises a longer slit and a shorter slit, and the distally positionedtab of the first extension member is inserted into the longer slit, andthe proximally positioned tab of the second extension member is insertedinto the shorter slit; and wherein the second end section of the innerlooped blade comprises a longer slit and a shorter second slit, and thedistally positioned tab of the second extension member is inserted intothe longer slit, and the proximally positioned tab of the firstextension member is inserted into the shorter slit.
 7. The tissuecutting device of claim 6, wherein the first end section of the outerlooped blade comprises a slit, that the distally positioned tab of thefirst extension member is inserted into, and wherein the second endsection of the outer looped blade comprises a slit, that the distallypositioned tab of the second extension member is inserted into.
 8. Thetissue cutting device of claim 1, wherein the distally and proximallypositioned tabs of the first extension member are positionedindividually on separate prongs, and the distally and proximallypositioned tabs of the second extension member are positionedindividually on separate prongs.
 9. The tissue cutting device of claim8, wherein the separate prongs of the first extension member havedifferent lengths to prevent collision during operation, and theseparate prongs of the second extension member have different lengths toprevent collision during operation.
 10. The tissue cutting device ofclaim 1, wherein, during operation, the first tube is configured tosheath the distal end sections of the first and second extension membersand the first and second end sections of the inner and outer loopedblades.
 11. The tissue cutting device of claim 10 wherein the first tubeis configured to move distally to collapse the inner and outer loopedblades and proximally to release and open the inner and outer loopedblades.
 12. The tissue cutting device of claim 1 wherein the first tubeis a stationary inner tube and the device further comprises a secondexternal tube that can slide or telescope over the internal tubecollapse and release the inner and outer looped blades.
 13. The tissuecutting device of claim 1, wherein the internal face of the first tubehas a plurality of internal protrusions along its length that areconfigured to create channels that guide the first and second extensionmembers and inner and outer looped blades to prevent them from bendingoff plane during reciprocating motion.
 14. The tissue cutting device ofclaim 1, wherein the internal face of the first tube has a plurality ofinternal grooves along its length that are configured to create channelsthat guide the first and second extension members and inner and outerlooped blades to prevent them from bending off plane duringreciprocating motion.
 15. The tissue cutting device of claim 1, whereinwithin the internal channel of the first tube, and on the same axis ofthe tube there are a plurality of immobile rods and configured tosupport the first and second extension members and inner and outerlooped blades to prevent them from bending off plane duringreciprocating motion.
 16. The tissue cutting device of claim 1, whereinthe first and second extension members have a section having asemicylindrical shaped cross-section configured to conform to theinternal channel of the first tube.
 17. A tissue cutting devicecomprising: an electric motor configured to be turned on and off; afirst tube having an internal channel traversing lengthwise fromproximal to distal ends; first and second extension members havingproximal and distal ends, left and right sides, and positionedsuperiorly and inferiorly to one another within the internal channel ofsuch that they traverse parallel with the length of the tube, whereinthe proximal ends of the extension members are operably coupled to theelectric motor that drives straight reciprocating motion of the firstand second extension members in alternate proximal and distal directionswith respect to each other, such that when the first extension member ispushed distally the second extension member is pulled proximally, andvice versa; an outer looped blade having a first end section operablycoupled to first extension member; and a second end section operablycoupled to the second extension member; and an inner looped blade,positioned proximally and adjacent to the outer looped blade, and havinga first end section operably coupled to the second extension member anda second end section operably coupled to the first extension member;wherein the outer and inner looped blades are positioned distally to thedistal end of the external tube, and configured to reciprocate inalternate clockwise and counter-clockwise directions and in oppositedirections with respect to each other as the first and second extensionmembers reciprocate proximally and distally; and where the left or rightside of the distal end of the first extension member has a lateral sidecutout with a length substantially equal to the distance of distal andproximal reciprocation of the first and second extension members, and anopposite lateral side without a cutout, and where the distal end of thesecond extension member has a lateral cutout with a length substantiallyequal to the distance of distal and proximal reciprocation of the firstand second extension members, and positioned on the opposite left/rightside of the first extension member's cutout, and an opposite lateralside without a cutout.
 18. The tissue cutting device of claim 17 wherethe first end section of the inner looped blade is coupled to thenon-cutout side of the superior extension member and where the other endof the inner looped blade is coupled to the non-cutout side of theinferior extension member and where the first end section of the outerlooped blade is coupled proximal and adjacent to the cutout of thesuperior extension member and the second end section of the outer loopedblade is coupled proximal and adjacent to the cutout of the inferiorextension member.